octane by the books

[wangless]

ok,

ive been reading and reading... about recommended octane for the past 2 hours... searching and searching about what to use... i found mostly what people used and not what the books have said... so... im asking for... what the manual says... so if you owner's manual would you help out... state the year of your 240 and what the recommendation is...

btw... im asking bc i read one guy say in his 89 manual said 87 octane is good... while a 90 said his gas door said 'premium unleaded fuel only'... my 90 gas door only says unleaded fuel only... i might be missing a few letters i suppose... and the s14 models recommend 93... but i just want to straighten everything once and for all... so...

state the year of your 240 and what the book says... hopefully i get all the years... thanks !

[GroundZero]

my 1991 fastback hicas 240's manual states atleast 91 octane, i use 93 since it's available here

[Hijacker]

my 93 states that I should use 91 rated octance (it SHOULD be the same among any car running a KA24DE), but you can go lower since you're not risking predetonation via compressed air. My old eclipse (1st gen running a 4G63 NA) ran on 89. my girlfriend at the time had a plymouth laser (same car) and ran 87 in it with no troubles.

I use 91 in my 240 primarily because of the turbo. i would run higher if it were available.

[wangless]

anybody with a '90 ?

[89S13SILVIA]

i have an 89 hb and it says 89 but reccomends 91

[lessthanjakejohn]

You should run 91 for hi-performace and hot weather, but It won't affect the car too much if you run 88-90, there may be power or mpg loss, but as long as there is no detonation there is not a lot of gain from going higher.

[Toahk]

I have an 89, and run on 87 octane, it runs great and there is No noticible different between 87 and 91, I get great MPG (25+ most the time). Just my input. The weather goes from 100+ degrees in the summer to almost freezing in the winter, and there is no problem with me running 87 all year round.

[JuJuBeeee]

use what your ecu is tuned for, if it recommends 87 and you are running 91, there is NO performance benefit WHATSOEVER

NONE

you are juss throwing extra money away

[wangless]

so basically all 240s recommend 91 octane ?

[89240sx]

My original manual that came with my 89 240sx says to use 87 octane or higher.

[JuJuBeeee]

so basically all 240s recommend 91 octane ?

i doubt it, i know that s14's do

[Rockenreno]

My fuel cap says 'premium unleaded fuel recommended for maximum performance' or something like that.

My roomate uses 87 octane and got 28.4 mpg on his last tank of gas... I use 89 and get about the same as him, depending on where I'm driving.

[Chingon]

'92 and recommends 91 oct. The manual states that in my area el paso tx and the south west, you can go as low as 85 due to altitude and other crap. However, my car seems to like 91 and lasts longer in my opinion.